As recording materials to obtain high quality images, there have been used so far silver salt recording materials and photo-sensitive resin recording materials, which need to be processed in a liquid after recording. Silver salt recording materials, for example, require a process to blacken exposed silver grains or a process to color-develop couplers to desired colors. And such processes need mostly a liquid processing agent. In the case of photo-sensitive resin recording materials, in which images are formed according to their attribute that the solubility or affinity to a developing solution is changed by exposure, a process to remove nonimage portions with a developing solution must be provided after exposure. But those processes which use a liquid yields a waste liquid which is not desirable for environmental sanitation.
Accordingly, thermal transfer recording has come to arouse considerable attention as an image forming method capable of dry-processing. However, in a thermal transfer recording method which uses a thermal head, resolution in recording is restricted by the integration degree of a thermal head. And, even with a thermal head having a high integration decree, improvement in image quality is limited because of interaction between adjacent heads.
As a measure to break through the limit of image quality with the thermal head, utilization of thermal patterns based on light-heat conversion is conceived. This comprises the steps of providing image information as a pattern of light and converting it into a pattern of heat to generate heat necessary to cause thermal transfer of information. As one of such thermal transfer recording methods using light-heat conversion, there has been proposed an image forming method which uses a heat-fusible transfer ribbon having a heat-fusible ink layer comprised of a wax-type binder dispersing carbon black in it and carries out recording by means of a flash-light irradiation through a light-transmittable original to form transferred images.
Further, a technique relating to a sublimation transfer sheet having an ink layer containing a light-absorbing exothermic substance is disclosed in Japanese Pat. O.P.I. Pub. No. 19533/1980.
However, these transferred image forming methods have a defect of insufficient sensitivity attributable to their low light-heat conversion efficiency.
On the other hand, there is demanded, in the method of forming multicolor images, a technique having a high retransferring efficiency in a proof manufacturing which comprises the processes of forming images of three primary colors on an image receiving layer and retransferring it to another support.